首页> 外文期刊>Trees - Structure and Function >Summer-drought constrains the phenology and growth of two coexisting Mediterranean oaks with contrasting leaf habit: implications for their persistence and reproduction
【24h】

Summer-drought constrains the phenology and growth of two coexisting Mediterranean oaks with contrasting leaf habit: implications for their persistence and reproduction

机译:夏季干旱限制了两种并存的地中海橡木的习性和生长,并具有相反的叶习性:对其持久性和繁殖的影响

获取原文
获取原文并翻译 | 示例

摘要

This study analyses how coexisting evergreen and deciduous oaks adjust their phenology to cope with the stressful Mediterranean summer conditions. We test the hypothesis that the vegetative and reproductive growth of the winter deciduous (Quercus faginea Lam.) is more affected by summer drought than that of the evergreen [Quercus ilex L. subsp. ballota (Desf.) Samp.]. First, we assessed the complete aboveground phenology of both species during two consecutive years. Shoot and litter production and bud, acorn and secondary growth were monitored monthly. Second, we identified several parameters affected by summer conditions: apical bud size, individual leaf area (LA), leaf mass per area (LMA) and acorn yield in both species, and leaf-fall in Q. faginea; and analysed their variation over 10 years. Q. ilex performed up to 25% of shoot growth and most leaf development during summer, whereas Q. faginea completed most of both phenophases during spring. Secondary growth was arrested in summer under drought conditions. Approximately, 30–40% of bud and 40–50% of acorn growth was undertaken during summer in both species. Summer drought related to differences in LA, LMA and leaf senescence, but not to acorn yield. Both species had similar year-to-year patterns of acorn production, though yields were always lower in Q. faginea. Bud size decreased severely in both species during extremely dry years. In Q. ilex, bud size tended to alternate between years of large and small buds, and these patterns were followed by opposite trends in stem length. In Q. faginea, bud size was more stable through time. Q. ilex was more phenologically active during summer than Q. faginea, indicating a higher tolerance to drought. Furthermore, bud and fruit growth (the only two phenophases that both species performed during summer) were more severely affected by summer drought in Q. faginea than in the evergreen. The differential effects of summer drought on key phenophases for the persistence (bud growth) and colonization ability (fruit production) of both species may have consequences for their coexistence.
机译:这项研究分析了常绿和落叶橡树共存如何调整其物候特征,以应对地中海夏季的压力。我们测试的假设是,冬季落叶的营养生长和繁殖生长比常绿的落叶栎(Quercus ilex L. subsp。)更受夏季干旱的影响。 ballota(Desf。)Samp。]。首先,我们评估了连续两年中两个物种的完整地上物候。每月监测芽和凋落物的产生以及芽,橡子和次生的生长。其次,我们确定了受夏季条件影响的几个参数:两种物种的根尖芽大小,单个叶面积(LA),每面积叶质量(LMA)和橡子产量,以及Q. faginea的落叶。并分析了他们10年的变化。夏季,Q。ilex的芽生长和叶发育最多可达到25%,而faginea的Q. faginea在春季则完成了大部分两个表相。夏季在干旱条件下阻止了次级生长。在两个物种中,大约在夏季都进行了30–40%的芽和40–50%的橡子生长。夏季干旱与LA,LMA和叶片衰老的差异有关,但与橡子产量无关。两种物种的橡子生产年比相似,尽管在Q. faginea中单产始终较低。在极度干旱的年份中,两个物种的芽大小均急剧下降。在冬青Q.冬青中,芽的大小倾向于在大芽和小芽的年之间交替变化,并且这些模式之后的茎长趋势相反。在Q. faginea中,芽的大小随着时间的推移更加稳定。冬青Q.冬青树比Q. faginea在物候学上更活跃,表明对干旱的耐受性更高。此外,Q。faginea的夏季干旱比常绿植物更严重地影响芽和果实的生长(两个物种在夏季都进行的仅有的两个表相)。夏季干旱对这两个物种的持久性(芽生长)和定植能力(果实产量)的关键性状期的不同影响可能会影响它们的共存。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号